refactor(assets): modular architecture + async two-phase scanner & background seeder (#12621)

app/database/db.py

@@ -3,6 +3,7 @@ import os
 import shutil
 from app.logger import log_startup_warning
 from utils.install_util import get_missing_requirements_message
+from filelock import FileLock, Timeout
 from comfy.cli_args import args
 
 _DB_AVAILABLE = False
@@ -14,8 +15,12 @@ try:
     from alembic.config import Config
     from alembic.runtime.migration import MigrationContext
     from alembic.script import ScriptDirectory
-    from sqlalchemy import create_engine
+    from sqlalchemy import create_engine, event
     from sqlalchemy.orm import sessionmaker
+    from sqlalchemy.pool import StaticPool
+
+    from app.database.models import Base
+    import app.assets.database.models  # noqa: F401 — register models with Base.metadata
 
     _DB_AVAILABLE = True
 except ImportError as e:
@@ -65,9 +70,69 @@ def get_db_path():
         raise ValueError(f"Unsupported database URL '{url}'.")
 
 
+_db_lock = None
+
+def _acquire_file_lock(db_path):
+    """Acquire an OS-level file lock to prevent multi-process access.
+
+    Uses filelock for cross-platform support (macOS, Linux, Windows).
+    The OS automatically releases the lock when the process exits, even on crashes.
+    """
+    global _db_lock
+    lock_path = db_path + ".lock"
+    _db_lock = FileLock(lock_path)
+    try:
+        _db_lock.acquire(timeout=0)
+    except Timeout:
+        raise RuntimeError(
+            f"Could not acquire lock on database '{db_path}'. "
+            "Another ComfyUI process may already be using it. "
+            "Use --database-url to specify a separate database file."
+        )
+
+
+def _is_memory_db(db_url):
+    """Check if the database URL refers to an in-memory SQLite database."""
+    return db_url in ("sqlite:///:memory:", "sqlite://")
+
+
 def init_db():
     db_url = args.database_url
     logging.debug(f"Database URL: {db_url}")
+
+    if _is_memory_db(db_url):
+        _init_memory_db(db_url)
+    else:
+        _init_file_db(db_url)
+
+
+def _init_memory_db(db_url):
+    """Initialize an in-memory SQLite database using metadata.create_all.
+
+    Alembic migrations don't work with in-memory SQLite because each
+    connection gets its own separate database — tables created by Alembic's
+    internal connection are lost immediately.
+    """
+    engine = create_engine(
+        db_url,
+        poolclass=StaticPool,
+        connect_args={"check_same_thread": False},
+    )
+
+    @event.listens_for(engine, "connect")
+    def set_sqlite_pragma(dbapi_connection, connection_record):
+        cursor = dbapi_connection.cursor()
+        cursor.execute("PRAGMA foreign_keys=ON")
+        cursor.close()
+
+    Base.metadata.create_all(engine)
+
+    global Session
+    Session = sessionmaker(bind=engine)
+
+
+def _init_file_db(db_url):
+    """Initialize a file-backed SQLite database using Alembic migrations."""
     db_path = get_db_path()
     db_exists = os.path.exists(db_path)
 
@@ -75,6 +140,14 @@ def init_db():
 
     # Check if we need to upgrade
     engine = create_engine(db_url)
+
+    # Enable foreign key enforcement for SQLite
+    @event.listens_for(engine, "connect")
+    def set_sqlite_pragma(dbapi_connection, connection_record):
+        cursor = dbapi_connection.cursor()
+        cursor.execute("PRAGMA foreign_keys=ON")
+        cursor.close()
+
     conn = engine.connect()
 
     context = MigrationContext.configure(conn)
@@ -104,6 +177,12 @@ def init_db():
             logging.exception("Error upgrading database: ")
             raise e
 
+    # Acquire an OS-level file lock after migrations are complete.
+    # Alembic uses its own connection, so we must wait until it's done
+    # before locking — otherwise our own lock blocks the migration.
+    conn.close()
+    _acquire_file_lock(db_path)
+
     global Session
     Session = sessionmaker(bind=engine)